Radio Frequency Identification (RFID) is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID Readers and Tags. Both these devices have to tune to the same frequency to communicate. These systems use many different frequencies for identification. They use LF—Low-frequency, also called NF—near frequency, High-frequency and currently becoming most popular, the UHF—Ultra-high-frequency.
Presently, in the field of Radio Frequency or so called the radio frequency Identification (RFID) technology; it has various crucial design concepts of antenna and readers, which has a great achievement in the concerned field.
Radio frequency refers to the frequency or rate of oscillation of electromagnetic waves within a specific range that correspond to frequency of altering current electrical signals used to produce and detect radio waves. An antenna is a transducer designed to transmit or receive electromagnetic waves. In other words, antennas convert electromagnetic waves into electrical currents and vice versa. Antennas are used in systems such as radio and television broadcasting, point-to-point radio communication, wireless LAN, radar, and space exploration. Antennas usually work in air or outer space, but can also be operated under water or even through soil and rock at certain frequencies for short distances.
Physically, an antenna is an arrangement of conductors that generate a radiating electromagnetic field in response to an applied alternating voltage and the associated alternating electric current, or can be placed in an electromagnetic field so that the field will induce an alternating current in the antenna and a voltage between its terminals.
Thomas Edison used antennas by 1885. Edison patented his system in U.S. Pat. No. 465,971. Antennas were also used in 1888 by Heinrich Hertz (1857-1894) to prove the existence of electromagnetic waves predicted by the theory of James Clerk Maxwell. Hertz placed the emitter dipole in the focal point of a parabolic reflector.
Moreover the antenna is the conductive element that enables to transmit and receive the radio frequency signals as a single system or one for transmits and another for receive.
Reader is a radio frequency transceiver to transmit radio frequency signals or to receive the encoded signals. The reader typically contains a module or receiver and a control unit with a coupling element. The reader has three main functions like energizing, demodulating and decoding.
U.S. Pat. No. 5,621,199 discloses a stationary compact radio frequency reader unit comprising an radio frequency reader including an radio frequency antenna, a stationary compact reader/write electronics and a interface controller where the said compact reader body portion is adapted to be mounted on standard identification wall mounts. The rotatably adjustable head contains an antenna, can be directed to different direction without moving the compact reader body. In one embodiment the RF reader unit includes a switching power supply located within the reader body portion.
U.S. Pat. No. 6,720,930, 6,069,564, 6,445,297 discloses the different type of antennas like omni directional for remote reader, a multi directional antenna to provide multi-diiectional RF communication to the source and a modular RFID antenna for multi directional RF communication.
CN patent No. 1858772 discloses a radio RF identification system including a reader, a first antenna, a second antenna and an identification controller, in which, the first antenna is connected with the reader generating control signals and transferring them via the first antenna, the second antenna receives the signals and the identification controller is integrated in the circuit elements of a portable electronic device and connected with the second antenna and selects a data signal based on the control signal to send it to the reader via the two antennas, which can avoid the traditional strip or wear of RFID labels to transmit signals even further.
U.S. patent No. 20070176748 discloses a radio frequency communication method to which a communication can be set up between a reader and an radio frequency device at least over a medium distance and over a short distance, the short distance communication being set up using an RFID transponder and an antenna, the medium distance communication being set up by the reader sending a command signal to the transponder in order to switch at least one microcontroller and a transceiver from a passive state to an active state.
In the above stated prior arts it states about the different antenna and reader devices used for the radio frequency identification. It further discloses the separate antenna and reader device can be incorporated within a short distance. These devices further having drawbacks such as limited RF cable length, deterioration of signal strength, due to short cable length and separate mounting of antenna and reader.
Hence there is a need in the art to develop a highly efficient radio frequency identifier which ameliorates the above stated problems, also convenient, user friendly as well as more efficient.
Therefore the current invention aims to provide a potential successor in the field of radio frequency, which comprises the reader electronics, integrated with dual circular bi-static antenna and further an integral DC to DC converter.